The present invention relates to an advancing mechanism for an automatic screw thread cutting machine which comprises a machine bed, a clamping carriage movable on the machine bed, at least one drive motor, a speed reducing gearing and a spindle with a thread cutting tool connected thereto, whereby the advancing mechanism, provided with at least one speed reducing gearing, connects the clamping carriage with a drive.
In screw thread cutting machines of the aforementioned kind, the adjustment of the advance of the clamping carriage for the desired thread pitch and length has been complicated and expensive. For this purpose changeover gears respectively cam controls have been necessary, which was either constructively disadvantageous or required stock keeping of a large amount of parts since various gears or cams had to be kept in stock for each screw thread of different pitch to be cut into the workpiece.